How to: EUCAST recommendations on the screening procedure E.Def 10.1 for the detection of azole resistance in Aspergillus fumigatus isolates using four well azole-containing agar plates.
Clin Microbiol Infect. 2018 Sep 27;:
Authors: Guinea J, Verweij PE, Meletiadis J, Mouton JW, Barchiesi F, Arendrup MC, Subcommittee on Antifungal Susceptibility Testing (AFST) of the ESCMID European Committee for Antimicrobial Susceptibility Testing (EUCAST), EUCAST-AFST, Arendrup MC, Arikan-Akdagli S, Barchiesi F, Castanheira M, Chryssanthou E, Friberg N, Guinea J, Järv H, Klimko N, Kurzai O, Lagrou K, Lass-Flörl C, Mares M, Matos T, Meletiadis J, Moore CB, Mouton JW, Muehlethaler K, Rogers TR, Andersen CT, Velegraki A
BACKGROUND: The emergence of azole resistant A. fumigatus isolates is a matter of significant concern in Europe, with countries reporting resistance rates (that can be as high as 30%) in hospitalised patients. Consequently, the treatment guidelines in the Netherlands, the country with the highest documented prevalence of azole resistant A. fumigatus, has just been revised to now recommend initial therapy with combination therapy until the susceptibility pattern is known. Therefore, susceptibility testing of clinically relevant isolates has been strongly recommended in the ESCMID-EFISG aspergillosis guidelines. Furthermore, mixed azole-susceptible and azole-resistant (isogenic as well as non-isogenic) infections have been reported to occur which implies that colonies of clinical cultures may harbour various phenotypes of azole susceptibility.
OBJECTIVES: The EUCAST-AFST (European Committee on Antimicrobial Susceptibility Testing Subcommittee on Antifungal Susceptibility Testing) has released a new screening method document (E.Def 10.1) for the detection of azole resistant A. fumigatus isolates and updated the QC tables for antifungal susceptibility testing with associated QC endpoints. This review described in detail how to perform the screening test.
SOURCES: This "How to document" is based on the EUCAST azole agar screening method document E.Def 10.1 and the QC tables for antifungal susceptibility testing document, v 2.0 (available at: http://www.eucast.org/ast_of_fungi/qcafsttables/) CONTENTS: The method is based on the inoculation of azole-containing and azole-free agars and visual determination of fungal growth after one and two days of incubation. It can easily be implemented in routine laboratories of clinical microbiology and has been validated for simultaneous testing of up to five A. fumigatus colonies using itraconazole and voriconazole (mandatory), and posaconazole (optional).
IMPLICATIONS: This easy-to-use screening procedure for the detection of azole resistance in clinical A. fumigatus isolates will allow rapid testing in the daily routine of the microbiology laboratory and thus facilitate earlier appropriate therapy.
PMID: 30268672 [PubMed - as supplied by publisher]